July 2

🤖 Image and text generated with AI

⬇ Download holy card: ·

⚔ Commemorated today: The Scourge of Kaseya (2021)

Saint BigSpender, Who Spent Money That Never Came

Patron of cryptocurrency wallets, unconfirmed transactions, and those who count their money before they have it.

Life

In July 2020 Oded Leiba of ZenGo revealed BigSpender (CVE-2020-12119): some Bitcoin wallets, Ledger Live among them, increased the balance the moment an incoming transaction appeared, before confirmation, and did not decrease it when that transaction was cancelled with Replace-By-Fee. The user saw money never truly received and could act on it, exposed to double spending.

Prayer

O Saint BigSpender, who shows riches not yet confirmed, teach our wallets to wait for the confirmation before rejoicing. Amen.

How to celebrate

Celebrated by updating the wallet to the fixed versions and counting only confirmed transactions, like the prudent cashiers of old.

Count the unconfirmed coin, and you end with an empty purse.

Technical record

Disclosed on: July 2 2020
CVE: CVE-2020-12119

Ledger Live before 2.7.0 does not handle Bitcoin's Replace-By-Fee (RBF). It increases the user's balance with the value of an unconfirmed transaction as soon as it is received (before the transaction is confirmed) and does not decrease the balance when it is canceled. As a result, users are exposed to basic double spending attacks, amplified double spending attacks, and DoS attacks without user consent.

Sources: zengo.com · github.com